1. Field of the Invention
The present invention relates to surgical instruments for applying surgical staples to body tissue, and more particularly to a sealed apparatus for applying an annular array of surgical staples.
2. Discussion of the Related Art
Surgical stapling devices for applying an annular array of staples to tissue are well known in the art. These devices typically include a stapling assembly and an anvil member at the distal end of the apparatus. The stapling assembly generally includes a circular array of staples and means for expelling the staples against the anvil member. The anvil member typically includes means for completing the circular anastomosis, i.e. an array of bucket-shaped members against which clinch the staples are formed after being expelled from the stapling assembly.
Surgical stapling devices for applying an annular array of staples are well known in gastric and esophageal surgery, for example, in classic or modified gastric reconstruction typically formed in an end, to-end, end-to-side or side-to-side manner. One such instrument is the Premium CEEA.RTM. surgical stapler, manufactured and sold by United States Surgical Corporation. In use, the instrument typically is positioned within the lumen of an organ such as the stomach, esophagus or intestine in order to perform the anastomosis. The tissue is positioned between the anvil and the stapling assembly and is typically tied off, for example, by a purse string suture. Thereafter, the anvil member is advanced toward the stapling assembly by rotation of a rotatable knob or wing nut assembly at the proximal end of the instrument. When proper approximation is achieved, the staples are expelled from the fastener assembly. A circular knife typically follows the application of the staples to excise unwanted tissue at the anastomosis site. The instrument is then removed from the lumen of the organ.
To a large degree, the recent explosion in laparoscopic surgical procedures may be attributed to the development of mechanical devices particularly adapted for use in a laparoscopic environment. For example, U.S. Pat. Nos. 5,084,057 and 5,100,520 to Green, et al. describe an endoscopic multiple clip applier which enabled the surgical community to fully realize the potential of endoscopic cholycystectomy. The Green '057 and '420 patents describe, inter alia, a gaseous seal means for obstructing the passage of gas from the insufflated body cavity.
Providing a sealing system for a circular anstomosis instrument is recognized in the art. The present invention provides a uniquely structured sealing system which not only effectively seals the instrument but is easy to manufacture and assemble and does not significantly increase the cost of the instrument.